A variety of techniques and apparatuses have been used to determine the authenticity of currency bills (or other documents). These techniques generally implicate optically scanning or imaging the documents along with the processing of the resulting scan or image data in comparison to certain metrics. If the metrics are satisfied (or not satisfied, as the case may be), then the document is identified as suspect. The document may then be discarded because it is presumed to not be authentic or it can be sent on for further handling and consideration, perhaps using other tests or analyses, to confirm that it is not authentic. A common concern with prior art document scanning and imaging techniques is accuracy. Another common concern with the prior art techniques is speed. A need exists in the art for a method and system for determining the authenticity of documents which possesses improved accuracy rates and further can be implemented in automated system which operate at high document processing rates. It would further be an advantage if the system and method could be implemented in compact document handling systems, and if the system and method were inexpensive.